Study of the hidden-order of URu2Si2 by point contact tunnel junctions

Abstract

URu2Si2 presents superconductivity at temperatures below 1.5 K, and a hidden order (HO) at about 17.5 K, both electronic phenomena are in uenced by Fano and Kondo resonances. At 17.5 K the HO was related in the past to a Peierls distortion that produces an energy gap deformed by the resonances. This order has been studied by more than 20 years, still without a clear understanding. In this work we studied the electronic characteristics of URu2Si2 in a single crystal, with tunneling and metallic point contact spectroscopies. In the superconducting state, we determined the energy gap, which shows the in uence of the Fano and Kondo resonances. At temperatures where HO is observed, the tunnel junctions spectra show the in uence of the two resonances. Tunnel junctions characteristics show that the Fermi surface nesting depends on the crystallographic direction.